The ass-to-grass thing will definitely build bigger legs and more defined legs (if that makes sense). However, to get the benefits of hormonal release and posterior chain strengthening, parallel works fine since, as you said, you can do heavier weights that way. It's more of a choice rather than one thing being better than another. Depends on your goals.
I only go to parallel because I want to use heavier weights and want explosive power in my legs, for instance.

People too weak to follow their own dreams will always try to discourage others.

If you get below parallel with your toes pointed outward at about a 45 and press your knees out as you descend you'll get to a point where there's a rebound effect....that's the bottom and sweet spot for me.

Watch yourself sideways in a mirror as you go down - at some point your spine will start to round, and that's the point beyond you don't want to go with reasonable weight on your shoulders. That's according to Bill De Simone - so if anyone wants to accuse me of making this up, please take it up with Bill instead.

BTW: Instead of loading insane amounts of weights on my shoulders, I prefer doing overhead squats with light weights, and with those I go down well beyond parallel.

BTW: Instead of loading insane amounts of weights on my shoulders, I prefer doing overhead squats with light weights, and with those I go down well beyond parallel.

I've tried to do OHS and I have a hard time getting to parallel, let alone below. (I can go ATG on regular barbell front and back squats) Any tips? I'd love to be able to do these and appreciate any advice.

I've tried to do OHS and I have a hard time getting to parallel, let alone below. (I can go ATG on regular barbell front and back squats) Any tips? I'd love to be able to do these and appreciate any advice.

Just use a really light weight - ideally just a broom or any other long stick. You need to lock out the elbows and really bring the arms back. When I tried it first I also struggled to even reach parallel while keeping the arms locked out behind, but I made quick progress. When you add weight: Be prepared to drop the barbell in front of you when you lose balance - trying to hold on to it and to put it down safely will put your wrists in danger.